Melanoma-Associated Spongiform Scleropathy
The sclera may undergo degeneration at the base of a uveal melanoma. This change is typically not apparent clinically, but histologically, it appears as a feathery separation and fragmentation of the scleral collagen fibers. Studies have shown increased amounts of glycosaminoglycans in these areas. The change is postulated to result from activation of proteinases such as matrix metalloproteinase-2 in the sclera and may facilitate scleral extension of uveal melanoma.
Figure 8-8 A calcific plaque of the sclera. A, Calcific plaques (arrow) are typically located just anterior to the insertion of the medial and lateral rectus muscles. B, Calcific deposits are noted in the sclera (arrowheads) anterior to the rectus muscle insertion (arrow) (von Kossa stain).
(Part A courtesy of Vinay A. Shah, MBBS; part B courtesy of Tatyana Milman, MD.)
Figure 8-9 Scleral staphylomas. Several regions of scleral thinning (arrows), which appear blue because of the under lying uveal tissue, are present posterior to the rectus muscle insertions (arrowheads) and in the equatorial sclera.
(Courtesy of Nasreen A. Syed, MD.)
Excerpted from BCSC 2020-2021 series: Section 4 - Ophthalmic Pathology and Intraocular Tumors. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.